I have a 8300 from t mobile germany, OS 4.5.0.174 xxx305; can not use BIS service my provider says that sim card is not matching with the device so edge is small all the time xxx305; can enter WAP though but xxx305; can not register my phone to BIS and xxx305; cant use such applications facebook live msn etc. do I need to downgrade the device? if yes to which version..thanks for the help